Guest serial console hangs

Guest serial console hangs

[Andre Przywara]

Hi,

for some weeks now I experience strange hangs in the HVM guest's serial 
console.
I use serial="pty" or serial="file:foo" to redirect an HVM Linux guest's 
output (with console=ttyS0,115200n8 on the guest kernel cmdline).
This usually works, but about half of the time the output (and it seems 
the guest, too) stops somewhere. I can continue guest operation by 
pressing a key in the guest's console (of course not in the file: case). 
Beside that it looks like it is one key behind, so to see the result of 
an ls for instance I have to press Enter twice.
Has anyone an idea what could cause it or how to debug this?

Thanks,
Andre.

P.S. I am using a (fairly) recent -unstable HV (about two weeks old), 
latest unstable xl tool set and a 2.6.32.19-pvops Dom0 kernel.

-- 
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 448-3567-12

Re: Guest serial console hangs

[Ian Jackson]

Andre Przywara writes ("[Xen-devel] Guest serial console hangs"):
> for some weeks now I experience strange hangs in the HVM guest's serial 
> console.

What is the guest kernel ?  There were bugs in Linux's serial port
driver which had these symptoms.

Ian.

Re: Guest serial console hangs

[Andre Przywara]

Ian Jackson wrote:
> Andre Przywara writes ("[Xen-devel] Guest serial console hangs"):
>> for some weeks now I experience strange hangs in the HVM guest's serial 
>> console.
> 
> What is the guest kernel ?  There were bugs in Linux's serial port
> driver which had these symptoms.
Good hint! That cured the problem. It was an older kernel (from 
ttylinux, serial console support added). I tried 2.6.36-rc3 and it 
worked like a charm! Thanks!

Just out of curiosity: Can you give me a hint when or where these bugs 
were fixed?

Regards,
Andre.

-- 
Andre Przywara
AMD-Operating System Research Center (OSRC), Dresden, Germany
Tel: +49 351 448-3567-12